Ultra-wide band electromagnetic jamming projector

ABSTRACT

A radio frequency (RF) jamming device includes a differential segmented aperture (DSA), a jammer source outputting a jamming signal at one or more frequencies or frequency bands to be jammed, and RF electronics that amplify and feed the jamming signal to the DSA so as to emit a jamming beam. The DSA includes an array of electrically conductive tapered projections, and the RF electronics comprise power splitters configured to split the jamming signal to aperture pixels of the DSA. The aperture pixels comprise pairs of electrically conductive tapered projections of the array of electrically conductive tapered projections. The RF electronics further comprise pixel power amplifiers, each connected to amplify the jamming signal fed to a single corresponding aperture pixel of the DSA. The RF jamming device may include a rifle-shaped housing, with the DSA mounted at a distal end of the barrel of the rifle-shaped housing.

This application is a continuation of U.S. application Ser. No.16/881,813 filed May 22, 2020 and titled “ULTRA-WIDE BANDELECTROMAGNETIC JAMMING PROJECTOR”, now issued as U.S. Pat. No.11,171,736, which claims the benefit of U.S. Provisional Application No.62/852,333 filed May 24, 2019 and titled “ULTRA-WIDE BANDELECTROMAGNETIC JAMMING PROJECTOR”. U.S. Provisional Application No.62/852,333 filed May 24, 2019 is incorporated herein by reference in itsentirety.

BACKGROUND

The following relates to the radio frequency (RF) jamming arts,broadband RF jamming arts, and the like.

RF jamming finds application in numerous areas, such as disruptingcontrol of radio-controlled vehicles such as unmanned aerial vehicles(UAVs), sometimes referred to as drones, disrupting illegal radiocommunications, and the like. Disruption of UAVs, for example, is animportant countermeasure for preventing UAV operation in the airspacearound airports, since a collision between a UAV and a commercial (orprivate) aircraft can severely damage or even bring down the aircraft.Similarly, countermeasures against UAVs are employed to protectgovernment buildings and other sensitive areas that may be deemedhigh-value targets of malicious drone operators.

Some known devices employing RF jamming to counter UAVs are described inStamm et al., U.S. Pat. No. 10,020,909 issued Jul. 10, 2018 and Morrowet al., U.S. Pat. No. 10,103,835 issued Oct. 16, 2018, both of which areincorporated herein by reference in their entireties.

Certain improvements are disclosed herein.

BRIEF SUMMARY

In accordance with some illustrative embodiments disclosed herein, aradio frequency (RF) jamming device comprises: a differential segmentedaperture (DSA); a jammer source configured to output a jamming signal atone or more frequencies or frequency bands which are to be jammed; andRF electronics configured to amplify and feed the jamming signal to theDSA whereby the DSA emits a jamming beam at the one or more frequenciesor frequency bands which are to be jammed. In some embodiments, the DSAcomprises an array of electrically conductive tapered projections, andin some embodiments the RF electronics comprise power splittersconfigured to split the jamming signal to aperture pixels of the DSAwherein the aperture pixels comprise pairs of electrically conductivetapered projections of the array of electrically conductive taperedprojections. In some embodiments, the RF electronics further comprisepixel power amplifiers wherein each pixel power amplifier is connectedto amplify the jamming signal fed to a single corresponding aperturepixel of the DSA. Some embodiments further include a rotatable turretthat enables the DSA to be rotated about a vertical axis to a desiredazimuth angle. In some embodiments, the DSA comprises a plurality ofDSAs arranged to provide RF jamming over a full 360 degree azimuth. Insome embodiments, the RF jamming device further comprises a rifle shapedhousing having a barrel, the DSA being mounted on the end of the barrel.In some of these latter embodiments, the DSA comprises an array ofelectrically conductive tapered projections facing outward from the endof the barrel.

In accordance with some illustrative embodiments disclosed herein, an RFjamming method comprises: generating a jamming signal at one or morefrequencies or frequency bands which are to be jammed; and amplifyingand feeding the jamming signal to a differential segmented aperture(DSA) whereby the DSA emits a jamming beam at the one or morefrequencies or frequency bands which are to be jammed. In some suchembodiments, the DSA comprises an array of electrically conductivetapered projections, and the amplifying and feeding comprises splittingthe jamming signal to aperture pixels of the DSA wherein the aperturepixels comprise pairs of electrically conductive tapered projections ofthe array of electrically conductive tapered projections. Someembodiments further comprise amplifying the jamming signal fed to eachaperture pixel individually using a corresponding pixel power amplifier.

BRIEF DESCRIPTION OF THE DRAWINGS

Any quantitative dimensions shown in the drawing are to be understood asnon-limiting illustrative examples. Unless otherwise indicated, thedrawings are not to scale; if any aspect of the drawings is indicated asbeing to scale, the illustrated scale is to be understood asnon-limiting illustrative example.

FIG. 1 diagrammatically illustrates a radio frequency (RF) jammingdevice. Inset A of FIG. 1 shows a perspective view of the illustrativedifferential segmented aperture (DSA) of the RF jamming device. Inset Bof FIG. 1 shows a variant embodiment of the electrically conductivetapered projections.

FIG. 2 diagrammatically shows a side sectional view of an embodiment ofthe electrically conductive tapered projections, along with adiagrammatic representation of the connection of the balanced port of achip balun between two adjacent electrically conductive taperedprojections forming an aperture pixel.

FIG. 3 diagrammatically illustrates a jamming station employing the DSAof FIG. 1 on a rotatable turret.

FIG. 4 diagrammatically shows arranging a plurality of DSAs of the typeshown in FIG. 1 to provide full 360 degrees azimuth jamming.

FIG. 5 diagrammatically shows a portable jamming device having a rifleform factor, which employs a DSA of the type shown in FIG. 1 .

DETAILED DESCRIPTION

With reference to FIG. 1 , a diagrammatic view of a jamming device 6 isshown, which employs a differential segmented aperture (DSA) 8 which isshown in diagrammatic side sectional view in the main drawing of FIG. 1and in diagrammatic perspective view in Inset A of FIG. 1 . Theillustrative DSA 8 includes a printed circuit board (PCB) 10 having afront side 12 and a back side 14, and an array of electricallyconductive tapered projections 20 having bases 22 disposed on the frontside 12 of the PCB 10 and extending away from the front side 12 of thePCB 10 and tapering to terminate in an apex 24. The electricallyconductive tapered projections 20 can have any type of cross-section(e.g. square so as to form faceted electrically conductive taperedprojections 20′ as four-sided pyramids having four facets, as in InsetB, circular, hexagonal, i.e. faceted with six facets, octagonal, i.e.faceted with eight facets, or so forth). The apex 24′ can be flat, as inthe nonlimiting illustrative example four-sided pyramid electricallyconductive tapered projection 20′ of Inset B, or can come to a sharppoint 20 as in the nonlimiting illustrative conical electricallyconductive tapered projections 20, or can be rounded or have some otherapex geometry. The rate of tapering as a function of height (i.e.distance “above” the base 22, with the apex 24 being at the maximum“height”) can be constant, or the rate of tapering can be variable withheight, e.g. the rate of tapering can increase with increasing height soas to form a projection with a rounded peak, or can be decreasing withincreasing height so as to form a projection with a more pointed tip.Similarly, as best seen in FIG. 1 , Inset A, the illustrative array ofthe electrically conductive tapered projections 20 is a rectilineararray with regular rows and orthogonal regular columns; however, thearray may have other symmetry, e.g. a hexagonal symmetry, octagonalsymmetry, or so forth. The sidewalls of the electrically conductivetapered projections 20 can have various sidewall shapes, e.g. a squarebase and square apex lead to having four flat slanted sidewalls; asanother example, if the base and apex are circular (or the base iscircular and the apex comes to a point) then the sidewall is suitably aslanted or tapering cylinder; as yet another example, for a hexagonalbase and a hexagonal or pointed apex six slanted sidewalls are suitable,and so forth.

With continuing reference to FIG. 1 , the RF aperture further comprisesRF circuitry, which in the illustrative embodiment includes chip baluns30 mounted on the back side 14 of the PCB 10. Each chip balun 30 has abalanced port P_(B) electrically connected with two neighboringelectrically conductive tapered projections 20 of the array ofelectrically conductive tapered projections via electrical feedthroughs32 passing through the PCB 10. Each chip balun 30 further has anunbalanced port P_(U) connecting with the remainder of the RF circuitry.As will be further described, each chip balun 30 thus drives an aperturepixel comprising a pair of projections 20 connected with its balancedport P_(B) by power received at its unbalanced port P_(U). Theillustrative RF circuitry further includes a software-defined radio(SDR) based jammer source 40 that generates a jamming signal atpre-defined or user-defined frequencies or frequency bands which are tobe jammed; one or more RF power splitter 42, 44 for splitting the powergenerated by the SDR based jammer source 40 to the unbalanced portsP_(U) of the chip baluns 30, and a power amplifier 46 driving theunbalanced port P_(U) of each chip balun 30. In FIG. 1 , theillustrative electrical configuration of the RF circuitry employs firstlevel 1×2 RF power splitters 42 and second level 1×N RF power splitters44 that further split the power to the baluns 30. It is alternativelycontemplated to employ a single power splitter or to employ two (asillustrated), three, or more levels of power splitters, depending uponthe number of aperture pixels to be driven and the rated powerspecifications for the power splitter components.

In the illustrative embodiment of FIG. 1 , a compact design is achievedin part by employing one or more printed circuit boards (PCBs) includingat least the illustrative PCB 10 on which are mounted the chip baluns30. Additional electronic components of the RF circuitry (e.g., thepower splitters 42, 44, the power amplifiers 46, and optionally alsocomponents of the SDR based jammer source 40, are suitably also mountedon the back side 14 of the PCB 10, and/or on one or more additionalcircuit boards (not shown), which may be mounted in parallel with andspaced apart from the illustrated PCB 10 using suitable standoffs; ormay be mounted elsewhere, with the components of the optional additionalPCB(s) (not shown) being electrically connected with the unbalancedports P_(U) of the chip baluns 30 by electrical wiring. The illustrativeRF aperture includes chip baluns 30 mounted on the back side 14 of thePCB 10. Alternatively, the baluns 30 may be otherwise implemented, e.g.,as baluns inscribed into the PCB 10. In another approach, RF circuitrydriving the RF aperture may be entirely differential signal chains, inwhich case the baluns can be omitted.

The jamming device 6 employs the DSA 8 as the jamming signal outputaperture. The balanced ports P_(B) of the chip baluns 30 connectadjacent (i.e. neighboring) pairs of electrically conductive taperedprojections 20 of the array to apply a differential RF signal receivedat the unbalanced port P_(U) of the chip balun 30 between the twoadjacent electrically conductive tapered projections 20. Operation ofpairs of electrically conductive tapered projections in radiating RFpower is described in Steinbrecher, U.S. Pat. No. 7,420,522 which isincorporated herein by reference in its entirety. The tapering of theelectrically conductive tapered projections 20 presents a separationbetween the two electrically conductive tapered projections 20 thatcontinuously varies with the “height”, i.e. with distance “above” thebase 22 of the electrically conductive tapered projections 20. Thisprovides the DSA 8 with broadband RF functionality since a large rangeof RF wavelengths can be coupled corresponding to the range ofseparations between the adjacent electrically conductive taperedprojections 20 introduced by the tapering. The DSA 8 thus hasdifferential RF transmit elements corresponding to the adjacent pairs ofelectrically conductive tapered projections 20. These differential RFtransmit elements are referred to herein as aperture pixels. Forexample, the illustrative rectilinear 6×6 array of adjacent electricallyconductive tapered projections 20 shown in Inset A of FIG. 1 has fiveaperture pixels along each row (or column) of six electricallyconductive tapered projections 20. More generally, for a rectilineararray of projections having a row (or column) of N electricallyconductive tapered projections 20, there will be a corresponding N-1aperture pixels along the row (or column).

The SDR based jammer source 40 advantageously employs a suitablyprogrammed microprocessor or microcontroller and associated digitalelectronics (e.g. random access memory or other electronic storage) togenerate a digital jamming signal at a desired set of one or morefrequencies to be jammed that is converted to an analog jamming signalusing digital-to-analog (D/A) circuitry. Use of a SDR advantageouslypromotes configurability as the choice of jamming frequencies (orfrequency bands) can be configured in software of the SDR. However, itis alternatively contemplated to employ an analog jammer source in placeof the SDR based jammer source 40.

In operation, the jammer source 40 is configured to output a jammingsignal at one or more frequencies or frequency bands which are to bejammed. The RF electronics 42, 44, 46 are configured to amplify and feedthe jamming signal to the DSA 8, whereby the DSA 8 emits a jamming beamat the one or more frequencies or frequency bands which are to bejammed. The configuration of the jammer source may be hard wired, e.g.the jammer source may be an analog RF circuit that generates an RFsignal at the one or more frequencies or frequency bands which are to bejammed. In the illustrative embodiment, the SDR based jammer source 40is configured by software programming of the SDR to generate a digitalsignal at the one or more frequencies or frequency bands which are to bejammed that is then converted to an analog RF signal by a D/A converter.In a variant embodiment, the SDR may generate the digital signal mappedto the one or more frequencies or frequency bands which are to bejammed, which is then converted to an analog RF signal by a D/Aconverter and then heterodyned in the analog domain to the one or morefrequencies or frequency bands which are to be jammed. These are merelysome non-limiting illustrative examples, and more generally any SDRbased RF signal generation system can be employed as the SDR basedjammer source 40. In some embodiments, the SDR includes a user interface(e.g., see the examples described with reference to FIGS. 3 and 5 ) viawhich a user can select the one or more frequencies or frequency bandswhich are to be jammed.

The described configuration employing the PCB 10 with its front side 12serving as a mounting surface for the electrically conductive taperedprojections 20 of the DSA 8 and the chip baluns 30 mounted on its backside 14 advantageously enables the jamming device 6 to be made compactand lightweight. As described next, embodiments of the electricallyconductive tapered projections 20 further facilitate providing a compactand lightweight jamming device 6.

FIG. 2 shows a side sectional view of one illustrative embodiment inwhich each electrically conductive tapered projection 20 is fabricatedas a dielectric tapered projection 50 with an electrically conductivelayer 52 disposed on a surface of the dielectric tapered projection 50.The dielectric tapered projections may, for example, be made of anelectrically insulating plastic or ceramic material, such asacrylonitrile butadiene styrene (ABS), polycarbonate, or so forth, andmay be manufactured by injection molding, three-dimensional (3D)printing, or other suitable techniques. The electrically conductivelayer 52 may be any suitable electrically conductive material such ascopper, a copper alloy, silver, a silver alloy, gold, a gold alloy,aluminum, an aluminum alloy, or so forth, or may include a layered stackof different electrically conductive materials, and may be coated ontothe dielectric tapered projection 50 by vacuum evaporation, RFsputtering, or any other vacuum deposition technique. FIG. 2 shows anexample in which solder points 54 are used to electrically connect theelectrically conductive layer 52 of each dielectric tapered projection20 with its corresponding electrical feedthrough 32 passing through thePCB 10. FIG. 2 also shows the illustrative connection of the balancedport P_(B) of one chip balun 30 between two adjacent electricallyconductive tapered projections 20 via solder points 56.

It is to be understood that the DSA manufacturing design of FIG. 2 ismerely an illustrative example, and numerous other approaches forfabricating the DSA 8 are contemplated. For example, the electricallyconductive tapered projections 20 may be solid metal cones (or otherwiseshaped tapered projections), formed as freestanding metal shells bysheet metal punching or other sheet metal processing techniques, or soforth. Moreover, the illustrative PCB 10 can be replaced by another DSAsubstrate, with electrical wiring provided to electrically connect theaperture pixels of the DSA to the RF electronics. These are merelyfurther illustrative examples.

In the illustrative design of FIG. 1 , each power amplifier 46 drives anindividual aperture pixel of the DSA 8. Said another way, each pixelpower amplifier 46 is connected to amplify the jamming signal fed to asingle corresponding aperture pixel of the DSA 8. Accordingly, the poweramplifiers 46 are also referred to herein as pixel power amplifiers 46.The gain provided by the pixel power amplifier 46 (in combination withany optional further amplifiers, not shown, optionally interposedbetween the SDR based jammer source 40 and the pixel power amplifier 46)is referred to herein as the aperture gain. As the jamming signal inputto each aperture pixel is individually amplified by its correspondingpixel power amplifier 46, the individual pixel power amplifiers 46 canbe of lower power rating as compared with an RF aperture that is drivenby a jamming signal amplified by a single power amplifier driving theentire RF aperture.

Moreover, the power at any point in space in the far field is anadditive combination of the power from each aperture pixel. This isreferred to as the spatial gain.

These two gains: aperture gain due to the size of the effectiveaperture, and spatial gain due to the combination of power from theindividual aperture pixels in the far field, are additive. Consequently,the Effective Isotropic Radiated Power (EIRP) in the far field is theadditive sum of the aperture gain and spatial gain in decibels. Thisenables the jamming device 6 to output high jamming power in the farfield while using relatively small pixel power amplifiers 46. Forexample, if a 16 pixel DSA, each having a 30 dBm power amplifierconnected as shown in FIG. 1 , configured as a 5″×5″ physical aperture(that is, five inch square physical aperture) operating with 100%efficiency (that is, the physical aperture equals the effectiveaperture), then the total EIRP in the far field will be the sum of thetwo gains. So, for a jamming frequency of 2.4 GHz, the calculatedaperture gain will be approximately 7 dBi and the spatial gain will beequal to 10*Log(16) or 12 dB. Since each pixel has a 30 dBm amplifierconnected, the total EIRP would be 30 dBm+12 dB+7 dB or 49 dBm. If eachof the power amplifiers has a 30 dB gain, and the splitting loss is 12dB (16 power divisions), an SDR would only have to source 30 dBm−30 dB+12 dB or 12 dBm to realize the full 49 dBm EIRP, neglecting smallinsertion losses.

Furthermore, this high EIRP can be provided over a wide beam angle. Asquare planar DSA results in a beam pattern that is directional innature. An estimate of the beam width (in radians) of a square, flat DSAis given by the following equation:

$\begin{matrix}{{{Beamwidth}({rad})} = {2 \cdot {\cos^{- 1}\left( {1 - \frac{\lambda^{2}}{2\pi A_{eff}}} \right)}}} & (1)\end{matrix}$where λ is the wavelength of the RF signal, and A_(eff) is the effectivearea of the RF aperture. As the effective area (A_(eff)) decreases, thebeamwidth increases (albeit with a lower gain as the total power isspread out into the larger beamwidth).

Still further, with reference back to FIG. 2 , the DSA 8 is a broadbandRF aperture due to the large range of frequencies that can couple withthe aperture pixels. FIG. 2 diagrammatically indicates that, at a“height” H above the base 22 of the electrically conductive taperedprojections 20, the projections 20 of the aperture pixel are spacedapart by a distance D(H). This spacing range from a minimum spacing atthe base 22 of D(0) to a maximum spacing at the apex 24 of D(H_(apex)).The band of wavelengths that can couple then corresponds to thecontinuous range of spacings [D(0),D(H_(apex))], and can be recast asthe aperture frequency band using the conversion fλ=c where f isfrequency, λ is the wavelength, and c is the speed of light.

The combination of the SDR based jammer source 40 (see FIG. 1 ) and thewide bandwidth of the DSA 8, along with the efficiently obtained highfar field power achievable with the DSA 8, enables the jamming device 6to be programmed in the field (or, alternatively, pre-programmed) to jamradio signals at any desired frequency, combination of frequencies, bandof frequencies, or set of disjoint bands of frequencies.

With non-limiting illustrative reference to FIGS. 3-5 , the jammingdevice 6 of FIG. 1 can be deployed in various ways. FIG. 3 illustrates adeployment on a rotatable turret 60 that enables a single planar DSA 8to be rotated about a vertical axis 62 so as to be positioned at adesired azimuth angle. The turret 60 may be a fixed mounting, or couldbe mounted in the bed of a truck or other vehicle (not shown) in orderto provide a mobile jamming station. The illustrative turret 60positions the DSA 8 to generate a horizontally directed jamming beam.Alternatively, the DSA 8 could be mounted at some other angle, e.g. at ashallow elevation to increase jamming capacity at higher elevations. Inanother contemplated variant, a further joint (not shown) could beprovided to enable tilting of the DSA 8 about a horizontal axis toenable jamming directed at a user-selected elevation. The geometry ofthe DSA 8 could also be tuned to provide an asymmetric beam. Forexample, a wider vertical beamwidth compared with a narrower horizontalbeamwidth could be achieved by making the DSA rectangular with a longerhorizontal dimension and a shorter vertical dimension. In one suitableimplementational approach, the power splitters 42, 44 and pixel poweramplifiers 46 shown in FIG. 1 are integrated with the planar DSA 8 (e.g.being mounted on the PCB 10 and, if needed, on an additional one or morePCBs mounted in parallel with the illustrated PCB 10 using suitablestandoffs. The SDR based jammer source 40 may be mounted remotely fromthe DSA 8, for example in the bed or cab of the vehicle in embodimentsin which the rotating turret 60 is vehicle-mounted. In this approach,for example, the SDR based jammer source 40 may comprise a notebookcomputer providing the microprocessor and non-transitory storage medium(e.g. hard drive or solid state drive, SSD) storing the SDR software,with the computer connected via a USB port or other digitalcommunication link with external intermediary RF circuitry including aD/A converter and an optional power (pre-)amplifier feeding into thebase-level power splitter(s) 42 of FIG. 1 . Advantageously, the computercould also run software providing control for the rotation mechanism ofthe turret 60, so that a user sitting in the cab of the vehicle couldset the azimuth direction of the DSA 8 via the turret 60 (and theelevation, if a further elevation adjustment is provided for the DSA 8)and select the frequency or frequencies or frequency band or bands to bejammed, as well as the total jamming power.

FIG. 4 illustrates an example in which four DSAs 8 are arranged at 0degree, 90 degree, 180 degree, and 270 degree azimuth angles (referencedto an arbitrary 0 degree azimuth angle) forming a cube so as to providefull 360 degree azimuth coverage. This assumes that each DSA 8 has ahorizontal beamwidth of at least 90 degrees. If the DSAs have a smallerhorizontal beamwidth than this, then additional planar DSAs may beadded, e.g. six planar DSAs at 0, 60, 120, 180, 240, and 300 degreeazimuth angles thereby forming a hexagon. In a variant embodiment, theillustrative flat DSAs 8 can be replaced by DSAs having a curved surfaceto increase the beamwidth (albeit possibly at the loss of some spatialgain). For example, the curved surface could be manufactured to beconformal with a curved surface of the fuselage of an aircraft orunmanned aerial vehicle (UAV), or to be conformal with the hull of anocean-going ship or submarine, or to be conformal with a surface of around or cylindrical orbiting satellite, or so forth. Each planar DSA 8in the embodiment of FIG. 4 includes the PCB 10 and the RF electronicsas shown in FIG. 1 , except that in the embodiment of FIG. 4 it iscontemplated for a single instance of the SDR based jammer source 40 todrive all four DSAs 8 of the embodiment of FIG. 4 by way of a further1×4 power splitter (not shown). In one contemplated practicalimplementation, the assembly shown in FIG. 4 is mounted on a fixed towerto provide omnidirectional jamming over the full 360 degrees of azimuth.

FIG. 5 illustrates an example of a portable jamming device having arifle form factor, which employs a single instance of the planar DSA 8.The rifle form factor is provided by a rifle-shaped housing 70 having abarrel 72, and the DSA 8 is mounted on the distal end of the barrel 72with the array of electrically conductive tapered projections 20 facingoutward from the end of the barrel 72. (Said another way, the array ofelectrically conductive tapered projections 20 are oriented to generatethe jamming beam directed outward from the barrel in the direction thata bullet would be fired if the rifle-shaped housing 70 were an actualrifle). In the illustrative embodiment, the SDR based jammer source 40(indicated diagrammatically by dashed lines in FIG. 5 to indicate aninternal component). The power splitters 42, 44 and pixel poweramplifiers 46 may be mounted integrally with the DSA 8 as described forthe embodiment of FIG. 3 , or may be disposed inside the rifle-shapedhousing 70 and connected with the DSA 8 by suitable wiring in the“barrel” of the rifle-shaped housing 70. Some portable jamming deviceshaving rifle form factors are described in Stamm et al., U.S. Pat. No.10,020,909 issued Jul. 10, 2018 and Morrow et al., U.S. Pat. No.10,103,835 issued Oct. 16, 2018, both of which are incorporated hereinby reference in their entireties. The rifle-shaped housing 70 furthersupports a trigger 74 by which an operator energizes the DSA 8 to emit ajamming beam. The illustrative rifle-shaped housing 70 further has adisplay 76 and user controls 78 mounted thereon by which a user can readand adjust settings of the SDR based jamming source 40, respectively.(While user controls 78 separate from the display 76 are shown, it iscontemplated for the display and the user controls to be integratedtogether, e.g. in the form of a touch-screen display in which usercontrols are displayed on the display and are operated by user touchesto the display). This enables the user to select the jamming frequency,frequencies, frequency band, or frequency bands in the field. (Otheruser interfacing hardware is contemplated, for example a mobile deviceapplication program or “app” running on a cellphone, tablet computer, orthe like may be used to interface wirelessly with the SDR based jammingsource 40). The portable jamming device of FIG. 5 can be useful, forexample, in disrupting operation of an unmanned aerial vehicles (UAV),sometimes referred to as a drone, if it is impinging upon the controlledairspace of a commercial airport or other security-sensitive location.

In some embodiments, it is contemplated for the jamming device 6 toprovide jamming capability over a broad spectrum of communications from4 MHz to 6 GHz, although a larger, smaller, or different broad spectrumoperation range is also contemplated. In one non-limiting illustrativeexample, the jamming device 6 provides jamming capability over a broadspectrum encompassing the unlicensed “Industrial ScientificManufacturing” (ISM) bands in which many drones are currently operated.Again, these are merely non-limiting illustrative examples, and thebroad spectrum of operation is suitably designed based on the shapes ofthe electrically conductive tapered projections 20 so as to design theD(H) function described with reference to FIG. 2 and by the operatingfrequency ranges of the SDR based jammer source 40 and powerdistribution/amplification RF electronics 30, 42, 44, 46.

The jamming device 6 operates in transmit mode to output a jamming beam.In some embodiments (including the illustrative embodiment), the jammingdevice 6 is not configured to receive an RF signal via the DSA 8. Forexample, the jamming device 6 does not include RF electronics configuredto receive an RF signal via the DSA 8. Similarly, the SDR of the SDRbased jammer source 40 is not programmed to process a received RFsignal.

In other embodiments, it is contemplated to provide receive capabilityto assist in the jamming process. For example, it is contemplated(although not illustrated) to include receive capability (e.g. theillustrated RF electronics can be configured to receive an RF signal viathe DSA 8, for example using suitable RF switches to switch out thetransmit power amplifiers 46 and switch in receive amplifiers (notshown), with the splitters 42, 44 being RF combiner/splitter componentsto enable conveying the received RF signal, and the SDR based jammingsource 30 being further programmed to process the received RF signal.For example, such RF receive capability may be useful in the embodimentof FIG. 5 to automatically set the one or more frequencies or frequencybands which are to be jammed. This can be done by receiving thebroadband signal at intervals while the trigger 74 is pulled (indicatingthe device is pointed at the UAV to be jammed). Under the assumptionthat the strongest RF signal in this state will be at the one or morefrequencies or frequency bands transmitted by the UAV, the SDR basedjammer source 40 can then automatically configure (by suitableprogramming of the SDR) to output a jamming signal at the one or morefrequencies or frequency bands which dominate the received RF signal, soas to jam those frequencies.

The preferred embodiments have been illustrated and described.Obviously, modifications and alterations will occur to others uponreading and understanding the preceding detailed description. It isintended that the invention be construed as including all suchmodifications and alterations insofar as they come within the scope ofthe appended claims or the equivalents thereof.

The invention claimed is:
 1. A radio frequency (RF) jamming devicecomprising: a differential segmented aperture (DSA); a jammer sourceconfigured to output a jamming signal at one or more frequencies orfrequency bands which are to be jammed; and RF electronics configured toamplify and feed the jamming signal to the DSA whereby the DSA emits ajamming beam at the one or more frequencies or frequency bands which areto be jammed; wherein the jammer source comprises a software definedradio (SDR) including a microprocessor or microcontroller programmed togenerate a digital jamming signal at the one or more frequencies orfrequency bands which are to be jammed and digital-to-analog circuitryto convert the digital jamming signal to the jamming signal.
 2. The RFjamming device of claim 1 further comprising: a rotatable turret thatenables the DSA to be rotated about a vertical axis to a desired azimuthangle.
 3. The RF jamming device of claim 2 wherein the rotatable turretfurther enables tilting of the DSA about a horizontal axis to a desiredelevation.
 4. The RF jamming device of claim 1 wherein the DSA comprisesa plurality of DSAs arranged to provide RF jamming over a full 360degree azimuth.
 5. The RF jamming device of claim 1 further comprising arifle shaped housing having a barrel, the DSA being mounted on the endof the barrel.
 6. The RF jamming device of claim 5 wherein the jammersource is housed inside the rifle shaped housing.
 7. The RF jammingdevice of claim 6 further comprising: a display and user controlsdisposed on the rifle shaped housing, wherein the display and usercontrols are operative to enable a user to select the one or morefrequencies or frequency bands which are to be jammed.
 8. The RF jammingdevice of claim 7 wherein the display and user controls comprise atouch-screen display providing the user controls.
 9. The RF jammingdevice of claim 6 wherein the rifle shaped housing includes a triggerthat is operable to energize the DSA to emit the jamming beam.
 10. TheRF jamming device of claim 9 wherein the SDR is programmed to: duringintervals while the trigger is operated, receive a broadband signalusing the DSA; and determine the one or more frequencies or frequencybands which are to be jammed as one or more dominant frequencies orfrequency bands of the received broadband signal.
 11. The RF jammingdevice of claim 1 wherein the SDR is programmed to: receive a broadbandsignal using the DSA; and determine the one or more frequencies orfrequency bands which are to be jammed as one or more frequencies orfrequency bands of the received broadband signal.
 12. The RF jammingdevice of claim 1 wherein the RF jamming device is not configured toreceive an RF signal via the DSA.
 13. A radio frequency (RF) jammingdevice comprising: a broadband RF aperture; a jammer source configuredto output a jamming signal at one or more frequencies or frequency bandswhich are to be jammed; and RF electronics configured to amplify andfeed the jamming signal to the broadband RF aperture whereby thebroadband RF aperture emits a jamming beam at the one or morefrequencies or frequency bands which are to be jammed; wherein thejammer source comprises: a microprocessor or microcontroller programmedto select the one or more frequencies or frequency bands which are to bejammed and to generate a digital jamming signal at the one or morefrequencies or frequency bands which are to be jammed; anddigital-to-analog circuitry to convert the digital jamming signal to thejamming signal.
 14. The RF jamming device of claim 13 furthercomprising: a rotatable turret that enables the broadband RF aperture tobe rotated about a vertical axis to a desired azimuth angle.
 15. The RFjamming device of claim 13 further comprising a rifle shaped housingcontaining the jammer source and the RF electronics and having a barrelat an end of which the broadband RF aperture is mounted.
 16. The RFjamming device of claim 15 further comprising: user controls disposed onthe rifle shaped housing and operative to enable a user to select theone or more frequencies or frequency bands which are to be jammed. 17.The RF jamming device of claim 13 wherein the microprocessor ormicrocontroller is further programmed to: receive a broadband signalusing the broadband RF aperture; and determine the one or morefrequencies or frequency bands which are to be jammed as one or moredominant frequencies or frequency bands of the received broadbandsignal.
 18. A radio frequency (RF) jamming method comprising: receivinga broadband signal using a broadband RF aperture; using a softwaredefined radio (SDR), determining one or more frequencies or frequencybands which are to be jammed as one or more dominant frequencies orfrequency bands of the received broadband signal; generating a digitaljamming signal at the one or more frequencies or frequency bands whichare to be jammed using the SDR; converting the digital jamming signal toa jamming signal; and amplifying and feeding the jamming signal to thebroadband RF aperture whereby the broadband RF aperture emits a jammingbeam at the one or more frequencies or frequency bands which are to bejammed.